comparsion of m395x and Gtx 980m

i am wondering why the m395x is underperforming than the 980m?about 20% in Windows 8 bootcamp via the stress test of unigine heaven.
In terms of the comparison of spec, most of the spec of the 395x is higher than the 980m.
2048 shader vs 15xx higher memory clock speed, higher floating point, texture rate ,mapping unit as well as the memory bandwidth; the only disadvantages are the rendering unit pixel rate and shader clock speed.
After my observation via the istat menu, while running the unigine test the processor of m395x is only 70% in use, is that meaning the driver is not yet optimized? Or any things I have missed? Plz advice

The 980m is a top of the line mobile gpu (well, it was. Still quite good though). The m395x has some higher stats in some areas but the actual shader performance and it's higher core speed is the main reason it's better. It's not a huge difference but 20% sounds about right real world.

But yes, the m395x driver is not fully optimized. There's been a couple driver updates the past few months from amd that we can't use on our bootcamp versions. Which sucks big time cuz they've done a lot to increase performance in gaming. Sadly we likely won't get any updated drivers for almost a year, the guys with the 295x 2014 model didn't get an upgraded driver till october of 2015 soooooooooo us guys on the 395x likely won't get anything new for a while either.

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